Low-light performance continues to be a challenge for CMOS image sensors. In particular, as pixel geometries continue to shrink, second-order sampling inaccuracies have caused readout noise to climb. And, while the SNR (signal-to-noise ratio) loss is somewhat countered in medium-to-bright light conditions by increased resolution, in office lighting conditions, the reduced electron capture of small pixels pushes signal levels so low that readout noise is dominating performance at a wider range of the illumination spectrum.